icon format

What is a .ICO file?

ICO is the Windows icon format for app icons and website favicons. It can hold several sizes in one file.

Full name
Icon File
Developed by
Microsoft
Released
1985
Extension
.ico
MIME type
image/x-icon
Transparency
Yes

How to open a ICO file

ICO is used by Windows and browsers; icon editors can open and export it.

What ICO files are used for

App icons

Crisp icons at every required size.

Favicons

Browser-tab and bookmark icons.

UI assets

Cursors, toolbars and system glyphs.

Strengths & limitations

✔ Strengths✖ Limitations
Supports transparencyLess common outside its niche

Need more than a conversion?

Remove the background from ICO images, upscale to 4K, or generate new visuals with SharkFoto AI.

Frequently asked questions

ICO is the Windows icon format for app icons and website favicons. It can hold several sizes in one file.

ICO is used by Windows and browsers; icon editors can open and export it.

ICO is optimised for its specific use rather than strictly lossless storage.

Use SharkFoto's free tools — upload your ICO file and convert it to a more convenient format in seconds. It's free, processed securely and never stored.

Yes — ICO supports transparent backgrounds.

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